And in the porches of my ears did pour the leprous distilment..
Laertes is giving Ophelia advice on her feelings about Hamlet. As Laertes and Ophelia are talking, their dad Polonius walks in and starts to tell Laertes that he has his permission to leave but yet, he hasn't. After Laertes leaves the room, Polonius starts telling Ophelia similar things as Laertes. Ophelia wasn't cooperating with Polonius which led him to demand her not to see or talk to Hamlet and Ophelia obeys him.
Hamlet is thinking about how he doesn't like their family tradition of a coronation because he thinks it makes them look like drunks. Then the Ghost appears but Hamlet isn't afraid. Hamlet wants to go with the Ghost but Horatio and Marcellus don't want him to go. But, Hamlet goes anyways, and Horatio and Marcellus follow.
When Hamlet talks to the Ghost, the Ghost tells Hamlet that King Claudius killed him. He explains that Claudius killed him with leprous distilment which thickened King Hamlet's blood. After the Ghost finished talking, Hamlet starts to think that the only important thing to him now is to revenge his father's murder. Hamlet asks Marcellus and Horatio to never speak of what they saw and he tells them that if he starts to act weird, for them not to have a reaction.